The U.S. Air Force is offering $5,000 for any information that will lead to the discovery of grenade launcher rounds that personnel accidentally dropped from their vehicle onto a Native American reservation in North Dakota.

Airmen from the 91st Missile Wing Security Forces team were traveling between two intercontinental ballistic missile sites when the back hatch of their Humvee opened, and a container of ammunition fell out on the Fort Berthold Reservation on May 1, the Washington Post reported.